Mechanical motion of photonic devices driven by optical forces provides a profound means of coupling between optical fields. The current focus of these optomechanical effects has been on cavity optomechanics systems in which co-localized optical and mechanical modes interact strongly to enable wave mixing between photons and phonons, and backaction cooling of mechanical modes. Alternatively, extended mechanical modes can also induce strong non-local effects on propagating optical fields or multiple localized optical modes at distances. Here, we demonstrate a multicavity optomechanical device in which torsional optomechanical motion can shuttle photons between two photonic crystal nanocavities. The resonance frequencies of the two cavities, one on each side of this 'photon see-saw', are modulated antisymmetrically by the device's rotation. Pumping photons into one cavity excites optomechanical self-oscillation, which strongly modulates the inter-cavity coupling and shuttles photons to the other empty cavity during every oscillation cycle in a well-regulated fashion.
Bibliographical noteFunding Information:
We acknowledge the funding support provided by the Young Investigator Program of the Air Force Office of Scientific Research (Award No. FA9550-12-1-0338). Parts of this work were carried out in the University of Minnesota Nanofabrication Center, which receives partial support from National Science Foundation (NSF) through the National Nanotechnology Infrastructure Network program, and the Characterization Facility, which is a member of the NSF-funded Materials Research Facilities Network via the Materials Research Science and Engineering Centers program. H.L. acknowledges the support of a Doctoral Dissertation Fellowship provided by the Graduate School of the University of Minnesota.
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